Mikhail Pletnev, founder of post-Soviet Russia's first private orchestra, is questioned by a Thai police officer in front of the muscian's Pattaya residence. Photograph: AP

A celebrated Russian pianist and conductor was charged today in Thailand with molesting a 14-year-old boy after police raided the musician's home and found incriminating photographs.

Mikhail Pletnev, 53, founder and artistic director of the Russian National Orchestra (RNO), was arrested on Monday at a badminton club in Pattaya, a resort on the east coast of the Gulf of Thailand where he owns several properties.

Police searched one of his homes, confiscating material in connection with an investigation into a paedophilia ring. Prosecutors told a court in Pattaya that the search yielded several "compromising" photographs of Pletnev with underage boys.

Pletnev, a Grammy winner who studied at the Moscow Conservatory and founded the RNO as post-Soviet Russia's first private orchestra in 1990, was released on bail of $9,000 (£6,000). He denied the charge, saying there had been a "misunderstanding". If convicted, he faces up to 20 years in prison.

Pletnev claimed in an interview with the newspaper after his arrest that police had found only one photograph of him and a 25-year-old Thai man in Switzerland several years ago. He suggested that images of child pornography might have been stored or viewed on a computer at his home without his knowledge. He said he had paid Traiphop to look after two of his properties while he was abroad.

Andrei Dvornikov, a senior Russian diplomat who attended the hearing, told Russia's RIA Novosti news agency that the musician had denied the molestation charge. "He expressed his hopes that this misunderstanding will be resolved," said Dvornikov.

The arrest caused disquiet in Moscow where the culture and foreign ministries said they had sent an urgent message to the Russian embassy in Thailand asking it to clarify the situation and give "maximum consular defence to the outstanding musician".

Pletnev is a "people's artist" – the highest arts accolade in Russia – and a member of the country's presidential advisory council on sport and the arts. He is considered one of the world's leading interpreters of Tchaikovsky.

He founded the RNO after performing for Mikhail Gorbachev at a summit in Washington in 1988, and gaining the Soviet leader's support for a private orchestra which performed for the first time two years later.

Pletnev's recording of Prokofiev's Peter and the Wolf and Beintus's Wolf Tracks, conducted by Kent Nagano and narrated by Sophia Loren, Bill Clinton and Gorbachev, won a Grammy in 2004.